Connecter switch



Jne 24, 1930. v. s. THARP CONNECTER SWITCH Fi1ed Deo. 12, 1927' lll A 1....@ n .uuunuwn MQ .vg

Patented June 24, 1930 UNITED STATES PATENT oi'frucE JICTOR S. THARP, OF ELMHURST, ILLINOIS, ASSIGNOR TO RESERVE HOLDING COM- PANY, OF KANSAS CITY, MISSOURI, A CORPORATION OF DELAWARE coivNEoriir-nv SWITCH AppncaamnI flied December 12, 1927. serial No. 2.39384.

4This invention relates in general to switches for` telephone systems, and is particularly concerned with the provision of a new and improved rotary connecter switch,

5 which may be considered as an improvement on the switch shown in the application of R. Stehlik, Serial N 0.40239, filed June 29,

1925, now Patent No. 1,716,986, June 11,

More specifically, an object of the invention is to provide a rotary connecter switch having both directive and automatic primary or vertical movements, and having` both directive and automatic secondary or rotary movements, wherein the switch rotates over successive levels in search of an idle trunk.

The provision of a connecter havinglthe foregoing characteristics makes it possible to form large groups of trunks bycombining two or more levels, or by combining one or more levels with a port-ionV of an adjacent level.

The means whereby the foregoing as well as other objects of 'the invention are attained is pointed out in the specification taken in conjunction with the drawing forming a part thereof.

Inv the drawing, Fig. 1 shows the circuit arrangement whereby the various features are attained. F ig. 2 is a fragmentary View showing theeleventh step rotary contacts.

The rotary connecter H is one ot a pluralityhot` similar switches which are accessible to selecto'i` switches, and is of the well known Strowger vertical land rotary type. The connecter carries the usual line wipers and in this case two test wipers, one of which is the usual private wiper 'and the other is a special wiper.V The irst'special wiper contact of each group of trunks leading to the same subscribers station is permanently grounded, the'intermediate contacts ot the group have neither battery nor ground potential thereon. In'the case of a subscriber having but one trunk the special test contact is grounded. The contacts accessible in one 'level are shown. For the sake ot illustration the lines accessible by way of the rst three contacts have been put into one group, the fourth line Yleads to a station `having but one line, and the remaining lines are a portion of a dilferent group. For illustrative purposes the first group of lines has been provided with an overflow metering arrange-v ment. This may be omitted if desired. The connecter may be seized by a selector switch and directively operated by 'means of vimpulses transmitted from a calling device to complete a connection with agdesired subscriber such as the one shown at A. This connecter is capable of automaticallyv selecting an idle line ina group of lines leading to the same subscriber, and it all lines in the group are busy, of notifying the calling party of this fact.

The .operations ot' the-,connecter H will now be explained in det-ail, and. it will be assumed for this purpose, that a subscriber (not shown) desires to obtain avconnection with a subscriber at A, and that the last two digits of the subscriber-stelephone number are 2 1, which indicates the position in the connecter ot the first of three trunks leading to the desired subscribers station.`

Then the connecter H is seized by a preceding selector over the trunk conductors 2 4, the line; relay 10 operates over a loop (not shown) completed over the talking conductors 2, 4. The line relay 10 upon operating completes a circuit for the slow acting release relay 20, which relay at contact 21 places ground upon the release conductor 3 thereby establishing a holding circuit for the preceding switches, and at front contact 2 3 prepares" the impulsing circuit. Aty Contact 22a circuit-is established for the slow acting change over relayBO, said circuit extending from ground at Contact 22, through the back contact 93 of relay 90, conductor 65, and closed double dog contacts DD to the relay 30.

. When the calling subscriber operatesthe calling device in accordancewith the next digitY in the called subscribers telephone number a series ot interruptions of theloop circuit is produced, causing the line relay 10 to deenergize a pluralityr of times in accordance with the digit dialled. At each deenergization, an impulse of current isv sent from ground at the back contact -12 to the ,.1

vertical magnet V. Upon the first operation of the vertical magnet the double dog springs DD open the initial energizing circuit for the relay 39, which relay being slow acting is maintained operated during the impulsing over a circuit extending through the front Contact 3l, back contact l1 which V`is closed every time the circuit of line relay 10 is opened, back contacts 53 and 93 to ground at front Contact 22 of relay 20. The vertical magnet V operates to raise the switch wipers 110-113 step by step until they are opposite the desired level of bank contacts. At the end of the series of impulses, the circuit for the relay 3() is maintained open at the contact 11 and said relay releases. Atcontact r32 theV impulsing circuit is switched to the rotary magnet. It may be mentioned at this time that the contacts DD are arranged f on the switch in the manner shown in the patent to Martin No. 1,650,995, Nov. 29, 1927, differing therefromt in that here they are normally closed instead of being normally open. vThe calling subscriber may now dial the final digit of the desired number. lVith each vretraction of the armature 12 an` impulse of current is sent to the rotary magnet over a circuit which extends by way of front contact 23, back contacts 58, 32, 57 62, 56, winding of low resistance relay 7 O, back contact 97, to the winding of the rotary magnet. The rotary magnet and the low resistance relay 70 operate in series, and with each impulse the magnet moves the wipers 11G-113,

` inclusive, over the bank of contacts in the seleete-d level. The relay 70 being slow acting is maintained operated during impulsing and at contact 71 prepares a busy test circuit for the busy relay 80, and at Contact 73 it bypasses the back contacts 56 and 62. It is assumed that the first three trunks in the level all extend to the same subscribers station and only one impulse issent to the rotary magnet. As vstated before, the first contact in each group engaged by the wiper 111 has ground potential thereon, and therefore when the wiper 111 engages the contact 120 a circuit is established over said wiper to the upper Winding of relay 50. Relay is a two-step relay and when its upper winding 1s energized only the contact 55 closes. The slow acting relay 70 not having fallen back yet, the closure-of the contact is of no effect at this time. At the front contact 71 the busy test relay 80 is connected to the test wiper 112. If the first trunk is busy the test wiper 112 finds ground potential and before the relay releases, the relay 80 operates from ground `on said wiper. A moment after the cessation yof the impulse, relay 70 releases. The relay 80 is maintained operated over a locking circuit extending through back contact 96,V lower back Contact controlled by the armature 71, front contact 81, inner contact of the rotary magnet, back Contact 63, conductor 74, out-er Contact of the rotary magnet, back contact 93, to ground at the front contact 22 of relay 20. At back Contact 72 a circuit is established for the lower winding of the relay 50, said circuit extending through the lower winding of said relay, front first step contact 55 and lower back contact controlled by armature 53, back Contact 72, front contact 83 to grounded conductor 74. The lower winding of relay 60 is energized in parallel with the lower winding of relay 50. The relay 50 upon fully operating establishes a locking circuit for itself, said circuit extending through its lower winding, front contacts 55 and 53, to ground by way of back contact 93. At contact 59 a holding circuit for relay 80 is established independent of contact 63. The relay 60' upon operating establishes a holding circuit for itself at front contact 63. The following stepping circuit is now completed for the rotary magnet: battery, windingof the rotary magnet, contact 97, front contacts 82, 56, 62, 57, back contact 32, front contact 58, back eleventh step rotary Contact, to grounded conductor G5. The rotary maget moves the wipers 1lO--113 one step, and near the end of its stroke its contacts break the circuit for the relay 60 which relay releases and thereby opens the rotary magnet circuit. The rotary magnetr releases and again completes a circuit for the relay 60 which relay again establishes a circuit for the rotary magnet. The slow acting relay does not release during the short interval that its circuit is open at the rotary magnet contacts. The alternate energization of the relay 60 and the rotary magnet continues until either the switching relay 90 operates over wiper 112 when an idle trunkis found, or vuntil the wiper 111 finds ground potential indicating that the last trunk of the group has been reached and is busy, or that the first trunk in the next group has been reached. Assume that the third trunk of the group is idle. When the third trunk is reached, wiper 112 receives battery potential from the line switch, and when the relay 60 releases, a circuit is established for the upper windingvof relay 90, said circuit extending from battery at the wiper 112, through the back contact 71, upper winding of relay 90, back contact 61, front contact 52, upper winding of relay 60, back contact 93, contact 22, to ground. The relay 9() uponI operating establishes a locking circuit for itself, through itslower winding. The relay 60 is differentially wound and does not operate over its upper winding, the same being provided to prevent the operation of the relay over the lower winding in the event the rotary magnet should restore its contacts before the relay-90 has had time to operate. The relay 90 opens the rotary magnet circuit and also the circuit for relays 80 and 50, places guarding ground trunk conductor 3 thereby guarding the conv potential upon the wiper 112, and Switches through the talking conductors. When the metering arrangement is provided, a high resistance relay 122 is connected to the last contact of each group engaged by the wiper 112 and when ground potential is placed upon the contact, relay 122 operates and connects the grounded low resistance marginal relay 123 to the contacts engaged by the wiper 111. The relay 123 does not operate, its circuit being open at the contact of the switching relay 90. The overflow meter OFM is not operated at this time. Upon the operation of they relay 90 ringing current is intermittently transmitted from the ringing equipment E through the upper winding of the relay 4() to the called station. At contact 91 a ring back tone is applied to the upper incoming talking conductor of the connecter. When the called subscriber answers, a direct current circuit for the ringcut-ofi" relay is completed over the called line loop. Relay 40 upon operating establishes a locking circuit for itself by way of its lower winding, cuts orf the ringing current, and completes the talking connection. The usual back bridge relay is provided.

When the conversationA is inished, both subscribers replace their receivers. be assumed that the calling subscriber replaces his receiver lirst. The line relay 10 releases immediately .and opens the circuitof the slow acting relay 20. Before the release of relay 20, an impulse of currentis sent to the slow acting relay 70, as follows: ground at back Contact 12, front contact 23, back contacts 58, 32, 57, 62, and 56, throughl the winding of relay 70 to battery by way of front Contact 97 ot' relay 90. The operation ot slow acting relay 70 is at this time of no effect. A moment later slow acting relay 20 releases and at Contact 21 removes ground from the release trunk conductor 3,

thus allowing the preceding switches to release. The opening of the contact 22 is of no effect at this time, said contact being,

shunted by the front contact 5 ot relay 1. Upon the release ot relay 20 the circuit for the relay 70 previously traced is opened at ythe, contact 23 and a moment later the relay 70 releases. Upon the release of relay 70 ground is .again placed upon the release neoter againstseizure until such time as the called party shall have replaced the receiver, said ground extending from the front contact 95 of relay 90, through the back contact 71, upper winding of relay 90, back contacts 61 and 52, to conductor 3. When the called subscriber at A replaces his receiver, the back-bridge relay 1 releases and at Contact 5 opens the holding circuit for the lower winde y ing of relay 90, thereby allowing that relay to release, and at its lower back contact completes a circuit for the release magnet. The

It will the wiper 111. given to the calling subscriber by way of the n connecter is thus restored to normal by the last party replacing the receiver.

An explanation will now be given of the operation of the connecter when all trunks in the called group are busy. As previously explained, the automatic rotary trunk hunt ing movement of the switch was obtained by the alternate operation and release of relay and the rotary magnet, this action being stopped upon the operation of the relay 90,` which relay operates from battery over the` wiper 112 when said wiper comes upon an idlek trunk. As was previously explained, when the last trunk ot a group is seized, the relay 122 places ground through the low re-v. sistance marginal relay 123 upon the contacty engaged by the wiper 111. It is to be remembered that during the automatic rotary motion of the switch the relays 50 and 80 are locked in their operated positions, and that,

just prior tothe opening of the contacts on Vthrough the lower winding of the relay, back Contact 72, front contact 63, front contact 51, contact 94, the wiper 111, to ground at the marginal relay 123. The marginal relay 123 95 operates in this circuit to 4operate the overflow meter OF M. The relay 60 maintains the rotary magnet operated. After a short interval of time the relay 80 releases, its cir cuit being maintained open at the contact of l the rotary magnet. At contact 82 the relay 8O opens the circuit for the rotary magnet and the magnet releases.l The original holding circuit for the lower winding for relay 60 .is again completed by way of the backg,

Contact of the rotary magnet to ground at contact 22 of relay 20. The rotary magnet is now prevented from operating because of the open contact 82 of relay 80, and the relay 60 is maintained operated independent The busy tone will now be busy tone machine B, back contact 8 4, and front Contact 64. Vhen the calling subscriber restores his receiver the relays 10 andy, 2O release in succession and'open the circuit for the relays 50 and 60 and establish a circuit for the release magnet. The connecter is thereby restored to its initial position.

The overflow metering arrangement in-f. cluding the relays 122 and 123 may be dispensed with if desired. In this case the last contact in a group of contracts engaged by the wiper 111 has neither battery nor ground potential thereon. In sucha case if the last trunk in a group of trunks is busy the wiper gardless of the busy or idle condition of this trunk the relay 60 is maintained Voperated over the wiper 111, thus preventing the rel'ay 90 from operating over its upper winding, and when the relay y8O falls back a moment l-ater the calling subscriber gets the busy signal in the manner pointed out before. Vhen the lbusy metering scheme is dispensed with a relay such as relay 122 is connected to the 0-0 contact engaged by the wiper 112 and said relay places ground upon the 0-0 contact engaged by the wiper 111. This is provided for the purpose of stopping the switch when it reaches the very last switching position. Y

An explanation will now be given of the manner vof operation of the connecter in case a group comprising ltrunksy in two or more successive levels is called. Upon being yoperated to the first trunk in the group and finding said trunk busy, the connecter automatically rotates in search of an idle trunk in the manner previously pointed out. As pr-eviously pointed out the automatic rotary trunk hunting movement continues until it is stopped :either bythe operation `of relay 90 from battery vover the wiper 112 indicating that an idle trunk has been found or until relay l6() is maintained operated from -groundover the w-iper 111 indicating that the last tru-nk of the selected group has been reached and is busy, or that the first trunk f in the succeeding group has been reached.

"an eleventh step.

` ka short Assume now'that all the trunks of the group in the level are busy. Since it is assumed `that the tenth trunk-in the level is not the last trunk of the group 'the wiper 111 will not find ground when the tenth contact is reached, and since the-wiper 112 fails to `find battery the relay 90 will not be operated. The rotary magnet therefore takes Vhen this occurs, the projection 130 (F ig. 2) on Vthe wiper shaft 'engages the spring 131, vand vmoves the same distance. In its movement the spring 131 rides upon the upwardly dented portion 132 thereby forcing the spring 135 downward, and thus vmoving the upwardly bent portion 133 4out of holding engagement with vthe spring 136, allowing the same toI snap to the right and actuate its contacts. A circuit is established for the vertical magnet as follows (Figure 1): from battery through 'the' vertical magnet, resistance 24, fronteleventhstep rotary contacts at spring 136 .to grounded conductor 65. Simultaneous with the -establishment of the vertical l maignet'c-ircu-ita circuit is established for the 7'conductor 65.

release magnet by way of the vertical off-V :norma-l contacts VON, back contact 33 and front contact vat spring 131 to the grounded The switch commences to release.v rlhe release Y.magnet causes the doubleldo'g contact DD y'to close,'thereby establishing 'a circuit for the slow acting relay 30, which relay at back Contact 32 maintains the rotary magnet circuit open. During the retained partly energized through the resistance 24 which resistance is of such value that the vertical magnet barely moves its armature, the object of energizing the magnet at this time being to render it fast acting when its circuit isclosed exclusive of the resist- When the switch reaches the rotary normal position, the projection 134: (Figure 2) moves the spring 136 to the left, and said spring vriding over the upward bent portion 133, forces the spring 135 downward. Then the spring 136 rides past the bent up portion 133 the spring 135 again snaps upward and locks the spring 136 in position. )Vhcn the contacts at 136 are restored to the position sho-wn in the drawings a circuit for the vertical magnet independent o-f the resistance 2l is established, saidcircuit extending from the vertical magnet through front contact 32, front contact 58, back contact at circuit for slow-acting relay 30 which relay a moment later releases, 4and at its ycontact 32 reestablishes the stepping circuit for the rotary 'magnet as previously traced. The rotary magnet takes one step yand rotates the wipers 11G-113 to the first contactin the bank. If the first trunk in the bank is busy, the rotary connecter will automatically hunt for lan idle trunk in this level in the manner previously pointed out. Since the switch-is now in 'the same condition as it Vwas in during the previous automatic trunk hunting movement, it may be seen that ifk an idle trunk is not found when the switch reaches the last trunk in `the level, and if the wiper 111 does not find `ground potential, theA switch will restore in its rotary movement and repeat the same operation inthe next level.

`Should the. connector H be operated by a calling subscriber to a trunk other than the first trunk of a group of trunks, as would be the case if a night number were called, 'the rotary connecteracts as an ordinary connecter and does not hunt for an idle trunk in the group. rThis may lbe seen from the following circuit arrangement: llhen the Vlast impulse has been transmitted the slow acting relay is in its operated position. The relay 50 is not operated at this time since there is no ground potential on wiper 111. If the called trunk is busy the Wiper 112 finds ground potential andthe relay 80 operates over a circuit previously traced. The relay'60 operates over its lower winding but does not complete a circuit for the rotaryrmagnet as before because the rotary magnet circuit is open at the contact 56 of relay 50. A moment later the slow acting relay 70 releases and opens the circuit for the slow acting relay 8O which a moment later also releases, its previously traced holding circuit being open at front contact 63. The relay 60 is maintained locked over a circuit extending through the back contact 72, front contact 63, to grounded conductor 74. The called party now receives the busy tone by way of back contact 84 and front contact 64.l If the called line, upon which the wipers 110-113 came to rest were idle, the wiper 112 would not have found ground potential, hence the relay 80 would not have operated. A-moment later, upon the release of relay 70, the relay 90 operates from battery over the wiper 112, back contact 71, upper winding of relay 90, back contacts 61 and52 to the grounded release conductor 3. The relay 90 completes a locking circuit at its lower winding, and, as pointed out previously, switches through the talking conductors and completes the ringing circuit to the called line.

In compliance with the requirements of the patent statutes I have herein described a preferred embodiment of my invention. I

do not, however, wish to be' limited to thev switch having access to said trunks, said switch'including a group selecting magnet and a trunk selectmg magnet, means for causing theswitch to hunt for an idle trunk,

said means including means for operating the group selecting magnet to select the groups one by one, means for directively operating the trunk selecting magnet to 'select the first trunk in the first group, means for automatically operating the trunk selecting magnet to hunt for an idle trunk in each group after the first as the group is selected, and means for stopping the hunting action of the switch responsive to an idle trunk being reached.

' 2. In a telephone system, a two-motion step-by-step trunk hunting switch having two operating magnets for operating the same in its two motions, respectively, means including one of said magnets for repeatedly operating the switch in one of its directions to its limit of motion and releasing the same, said action being automatically continuously repeated, means including the second mag- Y net for preventing ther complete release of the switch and for operating the switch one step in its other direction responsive toeacli sponsive to the finding of a desired trunk for stopping said switch.

3. In a telephone system, a multi-level trunk hunting switch, trunks accessible to said switch in each level, wipers for said switch, means for operating said switch responsive to two digits in a number to cause it to move said wipers in one level in search of an idle trunk, means effective upon said switch reaching its limit of motion Jfor retrunk for stopping the further trunk hunting movement of said switch..

et. In a telephone system, a vertical and a rotary multi-level' trunk hunting switch, trunks accessible to said switch in each level, wipers for said switch, a rotary magnet and a vertical magnet for said switch, means for automatically operating the rotary magnet to move said wipers in one level in search of an idle trunk, means effective upon said switch reaching its limit of rotary motion for restoring said switch in said level, for partially energizing said vertical magnet to prevent restoration below said level, l-'or operating the vertical magnet to move said switch to a different level, and for repeating the rotary motionin said different level, said action automatically continuing Jrom trunk to trunk and level to level, and means effective responsive to the wipers reaching an idle trunk for stopping the further trunk hunting movement of the switch.

5. In a telephone system, a connecter switch having a directive and an automatic primary movement and a directive and an automatic secondary movement, means for directively operating said switch in itsfprimary movement and in its secondary movement successively, means effective under pre-` determined conditions responsive to the cessation of the directive movement 'for automatically operating said switch in rits secondary movement, and means thereafter eillective under predeterminedconditions for continuing the operation Ioffsaid switch in its automatic primary movement.

6. In a telephone system, a connecter switch having a directive and an automatic primary movement and a directive and an automatic secondary movement, means for directively operating said switch in its primary movement and in its secondary movement successively, means eiective under predetermined conditions upon the cessation of the directive movements for automatically operating said switch in its secondary movement, means thereafter effective under predetermined conditions for continuing the operation of said switchl in its automatic pri- CII mary movement, and means thereafter effective ior again automatically operating said switch in its secondary movement.

7. In a telephone system, a rotary connecter, lines divided into groups and subgroups accessible to said connecters, some of said subgroups including lines in plurality of groups, a primary motor magnet for operating said connecter in a primary movement to select a group in accordance with a digit of the called number, a secondary movement in accordance with another digit of the called number to select a desired subgroup, means for continuing the secondary movement to automatically.v select an idle line in the selected subgroup, and means effective if an idle Atrunk in the selected group is not found for causing the primary magnet to select a different group and repeating the automatic secondary trunk hunting movement of said switch.

8. In a telephone system, a Vrotary connecter having a directive primary movement and a directive and automatic secondary movement, a test wiper, means controlled by the existence of a certain potential on the test wiper for instituting the automatic secondary movement of the switch, and circuit arrangements controlled by the recurrence of the same potential on the test wiper for stopping the switch. .Y

9. In a telephone system, :a rotary connecter having a directive' and an automatic primary movement, and a vdirective and an automatic secondary movement, a test wiper, means effective upon the termination of the directive secondary movement an-d controlled by the existence of a certain potential on the test wiper for instituting the automatic secondary movement of said switch, means controlled by the recurrence of the same potential on the test wiper for stopping the secondary automatic motion of the switch, and means effective if the said potential is not placed on the said wiper when the switch reaches its extreme secondary position for restoring the switch in its secondary motion, automatically operating the same in its primary motion, and then repeating the automat-ic secondary movement of the switch.

10. In a telephone system, a rotary connecter having a ydirective primary movement and directive and automatic secondary movements, a test wiper, means controlled by 'the existence of a certain potential on the test v wiper for instituting .the automatic secondary movement, circuit arrangements controlled by the recurrence of the same potential on the test wiper for stopping the switch,

an additional test wiper', and additional means controlled over the second wiper for stopping the automatic movement of said switch. Y

11.'In a telephone system, a rotary conand directive and automatic secondary movements, a test wiper., means controlled by the existence of a certain potential on the test wiper `for instituting the automatic secondary movement, circuit arrangements controlled by the recurrence of the sarnepoten-v and directive and automatic secondary movements, a test wiper, means controlled by the existence of a certain potential on vthe test wiper for instituting the automatic-secondary movement, circuit arrangementsv controlled by the recurrence of the same potential on the test wiper for stopping the switch,

an additional test wiper, additional means controlled over the second wiper for stopping the automatic movementof said switch, and means effective if the switch ywas stopped over one of said wipers for transmitting ringing current over the outgoing conductors of said switch and effective if the switch was stopped over the other of said wipers for transmitting busy signalling current over the incoming talking conductors of said switch. Y v v 13. In a telephone system, a rotary connecter having a directive primary movement and directive and automatic secondary movements, a test wiper, meansl controlledl by the existence of a certain potential on the test wiper for instituting the automatic secondary movement, Vcircuit v arrangements controlled by the recurrence of the same potential on the test wipe-r for stopping the switch, an additional test wiper, additional means controlled over thev second wiper for stopping the automatic movement of said switch, said additional means rbeing ineiiective if said test potential recurs upon said iirst mentioned test wiper, Vand means effective if the switch was stopped over one of said wipers for transmitting ringingcurrent over the outgoing conductors of said switch and effective if the switch was stopped over vthe other said wipers for transmittingbusy. signalling current over the incoming talking conductors of said switch.

14. In a telephone system, a step-by-s'tep rotary connecter having a direc-tive primary movement and directive` and automatic secondary movements, two test ',wipers, means effective underpredetermined conditions for instituting the automaticv secondary movement, means controlled over either wiper for stopping the automatic secondary movement, and means for testing over each of said wipers successively after each automatic step Y necter having a directive primary movcmentto determine if the stopping means/shall be i effective, the second test being omitted if the stopping means is effective responsive to the first test. V

15. In a telephone system, a step-by-step rotary connecter having a directive primary movement and directive and automatic secondary movements, two test wipers, means effective under predetermined conditions for instituting the automatic secondary movement, means controlled over either Wiper for stopping the automatic secondary movement, means fortesting over each of said wipers successively after each automatic step to determine if the stopping means shall be effective, the second test being omitted if the stopping means is effective responsive to the iirst test, and signalling means effective in either of two different manners for indicatl ing which of said two tests rendered said stopping means effective.

16. In a telephone system, a rotary connecter having directive primary movement and directive and automatic secondary movements, a group of trunks accessible to said connecter, a test wiper, test contacts over which the wiper moves, the test contact of the first trunk of said group having a certain potential thereon, means controlled by the existence of said certain potential on the test wiper for instituting the automatic secondary movement, means eective under predetermined conditions for placing saidl potential on the last contact of said group, and circuit arrangements controlledby the recurrence of the same potential on the test wiper for stopping the switch.

17. In an automatic switch, an operating magnet and a release magnet, means for energizing said operating magnet to operate said switch, means for energizing said release magnetto restore said switch, and means for partially energizing said operating magnet to prevent the complete restoration of said switch.

18. In a two motion switch, a primary magnet and a secondary magnet, means including said primary magnet for operating said switch in its primary movement, means including said secondary magnet for operating said switch in its secondary movement, means for restoring said switch, and means including said primary magnet for preventing the restoration of said switch in its primary movement.

19. In a switch having vertical and rotary movements, a vertical magnet and a rotary magnet, means including said vertical magnet for operating said switch in its vertical movement, means including said rotary magnet for operating said switch in its rotary movement, means for releasing said switch, and means for partially energizing said vertical magnet during therotary release of said switch to prevent the vertical release of the switch.

20. In a vertical and rotary switch, means including a vertical magnet for operating said switch in its vertical movement, means including a rotary magnet for operating said switch in its rotary movement, means for releasing said switch operative when said VICTOR S. THARP. 

